function dropElements( arr, func ) {
  for ( let i = 0; i < arr.length; i++ ) {
    if ( func( arr[ i ] ) ) { //first instance of true
      return arr.slice( i );
    }
  }
  return []; //if all false
}

console.log( dropElements( [ 1, 2, 3, 4 ], n => n > 5 ) );
